The Neurospora crassa Mitochondrial Genome*

*Based on Mitochondrial genetics of Neurospora , a review by A J. F. Griffiths, R. A. Collins, and F. E. Nargang , in "The Mycota II, Genetics and Biotechnology" (U. Kück, Ed.), pp. 93-105. Springer-Verlag. Berlin, Heidelberg, 1995. See also Hudspeth, M. E. S., 1992 The fungal mitochondrial genome—a broader perspective, in "Handbook of Applied Mycology. Volume 4: Fungal Biotechnology" ( D. K Arora, R. P. Elander, and K. G. Mukerji, eds.), pp. 213-241. Marcel Dekker, New York.

Appendix 4 Figure 1 Physical map of the mitochondrial DNA of wild type strain 74-OR23-1A. The corresponding genes are identified in Appendix 6 Table 1. For a map of restriction endonuclease cleavage sites of the same strain, see Taylor and Smolich (Curr. Genet. 9:597-603 1995). From Griffiths, Collins and Nargang (1995), with permission from Springer-Verlag..


Mitochondrial Genes of Neurospora  crassa

       Genea			       Equivalentb			         Encoded Product
Respiratory chain
		cox1      			coI		Cytochrome c oxidase subunit 1	
		cox2     			coII		Cytochrome c oxidase subunit 2
		cox3				coIII		Cytochrome c oxidase subunit-3

		cob				cob		Apocytochrome b

		ndh1				ND1		NADH dehydrogenase subunit 1
		ndh2				ND2		NADH dehydrogenase subunit 2
		ndh3				ND3		NADH dehydrogenase subunit 3 
		ndh4 				ND4		NADH dehydrogenase subunit 4
		ndh4l				ND4L		NADH dehydrogenase subunit 4L
		ndh5				ND5		NADH dehydrogenase subunit 5
		ndh6				ND6		NADH dehydrogenase subunit 6

ATP synthesis			
		atp6				ATP6		ATP synthase subunit 6		
		atp8				ATP8		ATP synthase subunit 8
		atp93				MAL		(ATP synthase subunit 9)3

Translational apparatus
		rnl				L-rRNA		Large ribosomal subunit RNA
		rns				S-rRNA		Small ribosomal subunit RNA

		S-5				S5  		Small ribosomal subunit protein

		tsld				tRNA		tRNA

Unidentified reading frame
		URF				URF j
						URF k
						URF L/M
						URF N
						URF u

Open reading frame
		ORFe				ORF


a Symbols used for fungal mitochondrial genes by Hudspeth 1992 and recommended for Neurospora.
b Symbols used for Neurospora mitochondrial genes in Figure 1 and in Griffiths et al. 1995.
c The Neurospora atp9 gene is translationally inactive. The translationally active gene for ATP synthase subunit 9 is the nuclear gene oli, which is closer in sequence to the translationally active mitochondrial gene ATP9 of Saccharomyces.
d "tRNA synthesis locus" (Hudspeth 1992).
e Several intron-encoded ORFs have been identified.

Mutant Mitochondrian Genomes of Neurospora crassaa

Group Mutant Growth Cytochromes

Suppression by
su([mi-1])-f su([mi-1])-1

I [poky](=[mi-1]) Lag Low aa3, and b, high c     +                         -
[SG-1,-3] Lag Low aa3, and b, high c     +                         -
[stp-B1] Lag Low aa3, and b, high c     +                         -
[exn-1,2,3,4] Lag Low aa3, and b, high c     +                         -
[C93] Temperature Sensitive Low aa3, and b, high c     ?                         ?
II [mi-3] Less Lag Low aa3, high b, normal c     -                         +
[exn-5] Loss Lag Low aa3, high b, normal c     -                         +
III [stp] Stop-start Low aa3, and b, high c     -                         -
[stp-A, -A18,-B2, -C] Stop-start Low aa3, and b, high c     -                         -
[abn-1, -2] Stop-start Low aa3, and b, high c     -                         -
[E35] Stop-start ?     ?                         ?
[ER-3] Stop-start ?     ?                         ?
[stp-107] Stop-start Low b and c, no aa3     ?                         ?

aThe mutations include nucleotide-pair substitutions, deletions, duplications, insertions, and complex rearrangements. The strains with mutant mitochondrial are cyanide-insensitive and salicyl hydroxamide-sensitive. They must thus rely on an alternate oxidase system. Except for Group II, they are all defective in mitochondrial protein synthesis. Inclusion of [C93] in Group I is tentative. Mutant names: SG, slow growth; stp, stopper: exn, extranuclear; mi, maternally inherited; abn, abnormal growth. Adapted from a table of Griffiths et al. 1995 and based on references given in that review.

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